The invention relates to a gear or profile grinding machine, especially for grinding of pre-geared or pre-profiled workpieces, wherein the machine comprises at least on tool spindle which can receive at least one grinding tool and wherein the machine comprises at least on workpiece spindle which is movable arranged at a carrier element and which can be driven up to the tool spindle for an at least temporary cooperation of the workpiece with the grinding tool by means of at least one drive. Furthermore, the invention relates to a method for operating such a gear or profile grinding machine.
Especially at the production of gears the final grinding process has a high importance. At this process the tooth flanks are subject to a grinding operation by which they are brought to the exact contour. An efficient method for the production of the gearing is the generative grinding by a grinding worm or the profile grinding with a profile grinding disc.
At workpieces especially with small gearings (tip diameter up to about 200 mm) the process main time is relatively short compared to the secondary times. Due to the relatively short main time machines and grinding methods are required for obtaining an economic production process which have an improved ratio between main time and secondary time. This applies specifically when additionally also the workpiece lot size decreases—as a consequence of a rising plurality of variants of the workpieces. Thereby, the reduction of the setup time becomes more and more important.
A gear grinding machine of the kind mentioned above as well as a method for the operation of the same are known from EP 2 305 409 B1. Here, already a solution is described which is characterized in that a favourable ratio between machining main time and secondary times can be obtained. Accordingly, an economical beneficial production is possible. Also the setup part can be kept small in relation to the machining main times. A similar solution shows DE 199 20 323 A1 which uses two workpiece spindles which are operated alternately.
However, it is detrimental at such a gear grinding machine with “pick up concept” that at rising diameters of the gears to be machined (especially at diameters from 125 mm upwards) the mass forces become so big at the handling of the workpieces that the required precision of the positioning suffers and the required level of quality cannot be ensured without elaborate measures. Accordingly, at machines with the design of EP 2 305 409 B2 the size of the workpieces is mostly limited for a process reliable gear grinding to a maximum diameter of 125 mm. It is difficult to machine exceeding workpiece dimensions in a process reliable manner due to the conceptual sensitivity to vibrations.
Thereby, it was found out that for some diseases no satisfying result is obtained. Here, especially the treatment of migraine is concerned which is sometimes not efficiently treatable when using conventional stimulation devices.